Capstan brake

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Author Message   Jerry Brown (jerrybrown11743) Member Username: jerrybrown11743 Post Number: 42 Registered: 03-2004 Posted on Thursday, February 21, 2008 - 04:23 pm:    The equation to be integrated is dx(Sx) = resistance. x is interpreted here as an angle. I want the value of resistance to be 0 for x = 0 to pi/2 and Sx*mu for x = pi/2 to pi. The problem runs for resistance = 0 and for resistance = Sx*mu. But, I can't get it ro run when I make resistance a function that depends on x. I've tried IF, RAMP and SWAGE. Any ideas? Capstan Brake Capstan brake model.pde (2.1 k)   Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1063 Registered: 06-2003 Posted on Thursday, February 21, 2008 - 11:41 pm:    I can't give you a complete description of what is happening, but it appears to be caused by the symbolic analysis totally removing the resistance term in some cells but not others. If you hide the IF (or SWAGE...) from the symbolic analyzer by defining a multiplier rfactor = if x > pi/2 then 1 else 0 and defining resistance = rfactor*Sx*mu the analyzer thinks Sx is always present, and does not remove the term. The attached files use IF and Swage, both successfully. Capstan_brake_model_1.pde (2.1 k) Capstan_brake_model_2.pde (2.2 k)   Jerry Brown (jerrybrown11743) Member Username: jerrybrown11743 Post Number: 43 Registered: 03-2004 Posted on Friday, February 22, 2008 - 01:13 pm:    Thank you! It works beautifully. I can even make resistance a function of Sx now. This opened a big door for me.